1. Field of the Invention
Our invention is a infrared radiation pyrometer.
2. Description of the Prior Art
Using single-wavelength or two-wavelengths infrared pyrometers is well known. In addition there are also infrared pyrometers which measure the entire infrared spectrum. As pointed out below, each of these instruments or systems has certain undesirable characteristics. None can simultaneously allow the measurement of both particle and gas temperatures within the short response time essential to observe explosions.
The single-wavelength infrared pyrometer has two distinct disadvantages. First the emissivity (ratio of the energy emitted by a surface to the energy emitted by an equal area of blackbody surface at the same temperature) of the hot object must be known. Also this same object must fill the entire field of view and have no intervening cloud of unburned particles between the hot flame and the pyrometer.
With the two-wavelength infrared pyrometers only particle temperatures are measured and not gas temperatures because they observe particle continuum radiation and not gas band radiation. Further these pyrometers do not supply enough results to compute the accuracy of the fit of the particle radiation to a Planck radiation curve since the standard deviation of the fit of the experimental points to the Plank curve can only be calculated if there are three or more wavelengths. Recently issued patents disclose two-wavelength pyrometers include, for example, the U.S. Pat. Nos. 3,501,237 (Lide) and 3,992,943 (Schiefer et al).
The infrared type of pyrometer which can measure the entire infrared spectrum may supply sufficient data to calculate both particle and gas temperatures. However, the delicate alignment of the optical components may not survive the shock of an explosion as the scanning spectrometers contain delicately aligned, moving parts which may be difficult to protect against the shock of an explosion. An additional disadvantage of this instrument is that it generates such a large amount of data for one scan that a large computer is necessary for the analysis of the data. In contrast our six-channel pyrometer with its faster response time than the scanning spectrometer allows the six data points we obtain with our invention to be converted to dust and gas temperatures by using a small, portable, programmable calculator.
In essence the difference between our invention and the known prior art resides in its construction to withstand the high pressure of an explosion and its ability to simultaneously record data used to calculate both particle and gas temperatures in the short response time necessary.